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        <h1>
          <span class="m-breadcrumb"><a href="Cookbook.html">Cookbook</a> &raquo;</span>
          Profile Taskflow Programs
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          <h3>Contents</h3>
          <ul>
            <li><a href="#ProfilerEnableTFProf">Enable Taskflow Profiler</a></li>
            <li><a href="#ProfilerEnableTFProfServer">Enable Taskflow Profiler on a HTTP Server</a></li>
            <li><a href="#ProfilerDisplayProfileSummary">Display Profile Summary</a></li>
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<p>Taskflow comes with a built-in profiler, <em>TFProf</em>, for you to profile and visualize taskflow programs.</p><img class="m-image" src="tfprof.png" alt="Image" style="width: 100%;" /><section id="ProfilerEnableTFProf"><h2><a href="#ProfilerEnableTFProf">Enable Taskflow Profiler</a></h2><p>All taskflow programs come with a lightweight profiling module to observer worker activities in every executor. To enable the profiler, set the environment variable <code>TF_ENABLE_PROFILER</code> to a file name in which the profiling result will be stored.</p><pre class="m-console"><span class="go">~$ TF_ENABLE_PROFILER=result.json ./my_taskflow</span>
<span class="go">~$ cat result.json</span>
<span class="go">[</span>
<span class="go">{&quot;executor&quot;:&quot;0&quot;,&quot;data&quot;:[{&quot;worker&quot;:12,&quot;level&quot;:0,&quot;data&quot;:[{&quot;span&quot;:[72,117],&quot;name&quot;:&quot;12_0&quot;,&quot;type&quot;:&quot;static&quot;},{&quot;span&quot;:[121,123],&quot;name&quot;:&quot;12_1&quot;,&quot;type&quot;:&quot;static&quot;},{&quot;span&quot;:[123,125],&quot;name&quot;:&quot;12_2&quot;,&quot;type&quot;:&quot;static&quot;},{&quot;span&quot;:[125,127],&quot;name&quot;:&quot;12_3&quot;,&quot;type&quot;:&quot;static&quot;}]}]}</span>
<span class="go">]</span></pre><p>When the program finishes, it generates and saves the profiling data to <code>result.json</code> in JavaScript Object Notation (JSON) format. You can then paste the JSON data to our web-based interface, <a href="https://taskflow.github.io/tfprof/">Taskflow Profiler</a>, to visualize the execution timelines of tasks and workers. The web interface supports the following features:</p><ul><li>zoom into a selected window</li><li>double click to zoom back to the previously selected window</li><li>filter workers</li><li>mouse over to show the tooltip of the task</li><li>rank tasks in decreasing order of criticality (i.e., execution time)</li></ul><p>TFProf implements a clustering-based algorithm to efficiently visualize tasks and their execution timelines in a browser. Without losing much visual accuracy, each <em>clustered</em> task indicates a group of adjacent tasks clustered by the algorithm, and you can zoom in to see these tasks.</p></section><section id="ProfilerEnableTFProfServer"><h2><a href="#ProfilerEnableTFProfServer">Enable Taskflow Profiler on a HTTP Server</a></h2><p>When profiling large taskflow programs, the method in the previous section may not work because of the limitation of processing large JSON files. For example, a taskflow program of a million tasks can produce several GBs of profiling data, and the profile may respond to your requests very slowly. To solve this problem, we have implemented a C++-based http server optimized for our profiling data. To compile the server, enable the cmake option <code>TF_BUILD_PROFILER</code>. You may visit <a href="install.html" class="m-doc">Building and Installing</a> to understand Taskflow&#x27;s build environment.</p><pre class="m-console"><span class="gp"># </span>under<span class="w"> </span>the<span class="w"> </span>build<span class="w"> </span>directory
<span class="go">~$ cmake ../ -DTF_BUILD_PROFILER=ON</span>
<span class="go">~$ make</span></pre><p>After successfully compiling the server, you can find the executable at <code>tfprof/server/tfprof</code>. Now, generate profiling data from running a taskflow program but specify the output file with extension .tfp.</p><pre class="m-console"><span class="go">~$ TF_ENABLE_PROFILER=my_taskflow.tfp ./my_taskflow</span>
<span class="go">~$ ls</span>
<span class="go">my_taskflow.tfp    # my_taskflow.tfp is of binary format</span></pre><p>Launch the server program <code>tfprof/server/tfprof</code> and pass (1) the directory of <code>index.html</code> (default at <code>tfprof/</code>) via the option <code>--mount</code> and (2) the <code>my_taskflow.tfp</code> via the option <code>--input</code>.</p><pre class="m-console"><span class="gp"># </span>under<span class="w"> </span>the<span class="w"> </span>build/<span class="w"> </span>directory
<span class="go">~$ ./tfprof/server/tfprof --mount ../tfprof/ --input my_taskflow.tfp</span></pre><p>Now, open your favorite browser at <code>localhost:8080</code> to visualize and profile your <code>my_taskflow</code> program.</p><img class="m-image" src="tfprof-local.png" alt="Image" /><p>The compiled profiler is a more powerful version than the pure JavaScript-based interface and it is able to more efficiently handle large profiling data under different queries. We currently support the following two view types:</p><ul><li>Cluster: visualize the profiling data using a clustering algorithm with a limit</li><li>Criticality: visualize the top-limit tasks in decreasing order of their execution times</li></ul></section><section id="ProfilerDisplayProfileSummary"><h2><a href="#ProfilerDisplayProfileSummary">Display Profile Summary</a></h2><p>You can display a profile summary by specifying only the environment variable <code>TF_ENABLE_PROFILER</code> without any value. The Taskflow will generate a separate summary report of tasks and workers for each executor created by the program.</p><pre class="m-console"><span class="gp"># </span><span class="nb">enable</span><span class="w"> </span>the<span class="w"> </span>environment<span class="w"> </span>variable<span class="w"> </span>without<span class="w"> </span>any<span class="w"> </span>value
<span class="go">~$ TF_ENABLE_PROFILER=    ./my_taskflow_program  </span>

<span class="gp"># </span>your<span class="w"> </span>program<span class="w"> </span>output
<span class="go">...</span>
<span class="go">... </span>
<span class="go">...</span>
<span class="gp"># </span>Taskflow<span class="w"> </span>profile<span class="w"> </span>summary
<span class="go">==Observer 0: 1 workers completed 18 tasks in 28 us</span>
<span class="go">    -Task-  Count  Time (us)   Avg (us)  Min (us)  Max (us)</span>
<span class="go">    static      7          5   0.714286         0         4</span>
<span class="go"> condition     11          0   0.000000         0         0</span>

<span class="go">  -Worker-  Level      Task  Count  Time (us)  Avg (us)  Min (us)  Max (us)</span>
<span class="go">        14      0    static      7          5  0.714286         0         4</span>
<span class="go">                  condition     11          0  0.000000         0         0</span>
<span class="go">                                18          5  0.277778         0         4</span></pre><p>The report consists of two sections, task summary and worker summary. In the first section, the summary reports for each task type the number of executions (<code>Count</code>), the total execution time (<code>Time</code>), average execution time per task (<code>Avg</code>), and the minimum (<code>Min</code>) and the maximum (<code>Max</code>) execution time among all tasks. Similarly in the second section, the summary reports for each worker the task execution statistics.</p></section>
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